The Fourth Amendment says, "[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

A seizure occurs when the government takes possession of items or detains people.

A search is any intrusion by the government into something in which one has a reasonable expectation of privacy.

Some examples of searches include: reaching into your pockets or searching through your purse; entering into your house, apartment, office, hotel room, or mobile home; and examining the contents of your backpack or luggage. Depending on the facts, eavesdropping on your conversations or wiretapping of your communications can also constitute a search and seizure under the Fourth Amendment.

The Fourth Amendment requires searches and seizures to be "reasonable", which generally means that police must get a search warrant if they want to conduct a legal search or seizure, although there are exceptions to this general rule. If a search or seizure is "unreasonable" and thus illegal, then police cannot use the evidence obtained through that search or seizure in a criminal trial. This is called the exclusionary rule and it is the primary incentive against government agents violating your Fourth Amendment rights.

A few important things to remember:

The Fourth Amendment protects you from unreasonable searches whether or not you are a citizen. In particular, the exclusionary rule applies to all criminal defendants, including non-citizens. However, the exclusionary rule does not apply in immigration hearings, meaning that the government may introduce evidence from an illegal search or seizure in those proceedings.

The Fourth Amendment applies whenever the government - whether local, state or federal - conducts a search or seizure. It protects you from an unreasonable search or seizure by any government official or agent, not just the police.

The Fourth Amendment does not protect you from privacy invasions by people other than the government, even if they later hand over what they found to the government - unless the government directed them to search your things in the first place.

Your Fourth Amendment rights against unreasonable searches and seizures cannot be suspended - even during a state of emergency or wartime - and they have not been suspended by the USA PATRIOT Act or any other post-9/11 legislation.

If you are ever searched or served with any kind of government order, contact a lawyer immediately to discuss your rights. Contact a lawyer any time you are searched, threatened with a search, or served with any kind of legal papers from the government or anyone else. If you do not have a lawyer, pro bono legal organizations such as EFF are available to help you or assist in finding other lawyers who will.

The Fourth Amendment only protects you against searches that violate your reasonable expectation of privacy. A reasonable expectation of privacy exists if 1) you actually expect privacy, and 2) your expectation is one that society as a whole would think is legitimate.

This rule comes from a decision by the United States Supreme Court in 1967. Katz v. United States, holding that when a person enters a telephone booth, shuts the door, and makes a call, the government can not record what that person says on the phone without a warrant. Even though the recording device was stuck to the outside of the phone booth glass and did not physically invade Katz’s private space, the Supreme Court decided that when Katz shut the phone booth’s door, he justifiably expected that no one would hear his conversation, and that it was this expectation - rather than the inside of the phone booth itself - that was protected from government intrusion by the Fourth Amendment. This idea is generally phrased as "the Fourth Amendment protects people, not places."

A big question in determining whether your expectation of privacy is "reasonable" and protected by the Fourth Amendment arises when you have "knowingly exposed" something to another person or to the public at large. Although Katz did have a reasonable expectation of privacy in the sound of his conversation, would he have had a reasonable expectation of privacy in his appearance or actions while inside the glass phone booth? Probably not.

Thus, some Supreme Court cases have held that you have no reasonable expectation of privacy in information you have "knowingly exposed" to a third party - for example, bank records or records of telephone numbers you have dialed - even if you intended for that third party to keep the information secret. In other words, by engaging in transactions with your bank or communicating phone numbers to your phone company for the purpose of connecting a call, you’ve "assumed the risk" that they will share that information with the government.

You may "knowingly expose" a lot more than you really know or intend. Most information a third party collects - such as your insurance records, credit records, bank records, travel records, library records, phone records and even the records your grocery store keeps when you use your "loyalty" card to get discounts - was given freely to them by you, and is probably not protected by the Fourth Amendment under current law. There may be privacy statutes that protect against the sharing of information about you - some communications records receive special legal protection, for example - but there is likely no constitutional protection, and it is often very easy for the government to get a hold of these third party records without your ever being notified.

Here are some more details on how the Fourth Amendment will - or won't - protect you in certain circumstances:

Residences. Everyone has a reasonable expectation of privacy in their home. This is not just a house as it says in the Fourth Amendment, but anywhere you live, be it an apartment, a hotel or motel room, or a mobile home.

However, even things in your home might be knowingly exposed to the public and lose their Fourth Amendment protection. For example, you have no reasonable expectation of privacy in conversations or other sounds inside your home that a person outside could hear, or odors that a passerby could smell (although the Supreme Court has held that more invasive technological means of obtaining information about the inside of your home, like thermal imaging technology to detect heat sources, is a Fourth Amendment search requiring a warrant). Similarly, if you open your house to the public for a party, a political meeting, or some other public event, police officers could walk in posing as guests and look at or listen to whatever any of the other guests could, without having to get a warrant.

Business premises. You have a reasonable expectation of privacy in your office, so long as it’s not open to the public. But if there is a part of your office where the public is allowed, like a reception area in the front, and if a police officer enters that part of the office as any other member of the public is allowed to, it is not a search for the officer to look at objects in plain view or listen to conversations there. That’s because you’ve knowingly exposed that part of your office to the public. However, if the officer does not stay in that portion of the premises that is open to the public - if he starts opening file cabinets or tries to go to private offices in the back without an invitation - then his conduct becomes a search requiring a search warrant.

Trash. The things you leave outside your home at the edge of your property are unprotected by the Fourth Amendment. For example, once you carry your trash out of your house or office and put it on the curb or in the dumpster for collection, you have given up any expectation of privacy in the contents of that trash. You should always keep this in mind when you are disposing of sensitive documents or anything else that you want to keep private. You may want to shred all paper documents and destroy all electronic media. You could also try to put the trash out (or unlock your trashcan) right before it’s picked up, rather than leaving it out overnight without a lock.

Public places. It may sound obvious, but you have little to no privacy when you are in public. When you are in a public place - whether walking down the sidewalk, shopping in a store, sitting in a restaurant or in the park - your actions, movements, and conversations are knowingly exposed to the public. That means the police can follow you around in public and observe your activities, see what you are carrying or to whom you are talking, sit next to you or behind you and listen to your conversations - all without a warrant. You cannot necessarily expect Fourth Amendment protection when you’re in a public place, even if you think you are alone. Fourth Amendment challenges have been unsuccessfully brought against police officers using monitoring beepers to track a suspect’s location in a public place, but it is unclear how those cases might apply to more pervasive remote monitoring, like using GPS or other cell phone location information to track a suspect’s physical location.

Infiltrators and undercover agents. Public meetings of community and political organizations, just like any other public places, are not private. If the government considers you a potential criminal or terrorist threat, or even if they just have an unfounded suspicion that your organization might be up to something, undercover police or police informants could come to your public meetings and attempt to infiltrate your organization. They may even wear hidden microphones and record every word that’s said. Investigators can lie about their identities and never admit that they’re cops - even if asked directly. By infiltrating your organization, the police can identify any of your supporters, learn about your plans and tactics, and could even get involved in the politics of the group and influence organizational decisions. You may want to save the open-to-the-public meetings for public education and other non-sensitive matters and only discuss sensitive matters in meetings limited to the most trusted, long-time staff and constituents.

Importantly, the threat of infiltrators exists in the virtual world as well as the physical world: for example, a police officer may pose as a online "friend" in order to access your private social network profile.

Records stored by others. As the Supreme Court has stated, "The Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities, even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third party will not be betrayed." This means that you will often have no Fourth Amendment protection in the records that others keep about you, because most information that a third party will have about you was either given freely to them by you, thus knowingly exposed, or was collected from other, public sources. It doesn’t necessarily matter if you thought you were handing over the information in confidence, or if you thought the information was only going to be used for a particular purpose.

Therefore it is important to pay close attention to the kinds of information about you and your organization’s activities that you reveal to third parties, and work to reduce the amount of private information you leave behind when you go about your daily business.

Opaque containers and packages. Even when you are in public, you have a reasonable expectation of privacy in the contents of any opaque (not see-through) clothes or containers. So, unless the police have a warrant or qualify for one of the warrantless search exceptions discussed below, they can’t go digging in your pockets or rummaging through your bags.

Laptops, pagers, cell phones and other electronic devices are also protected. Courts have generally treated electronic devices that hold data as if they were opaque containers.

However, always keep in mind that whatever you expose to the public isn’t protected. So, if you’re in a coffee shop using your laptop and an FBI agent sitting at the next table sees what you are writing in an email, or if you open your backpack and the FBI agent can see what’s inside, the Fourth Amendment won’t protect you.

Postal mail. The mail that you send through the U.S. Postal Service is protected by the Fourth Amendment, and police have to get a warrant to open it in most cases.

If you’re using the U.S. Postal Service, send your package using First Class mail or above. Postal inspectors don’t need a search warrant to open discount (media) rate mail because it isn’t supposed to be used for personal correspondence.

Keep in mind that although you have privacy in the contents of your mail and packages, you don’t have any privacy in the "to" and "from" addresses printed on them. That means the police can ask the post office to report the name and address of every person you send mail to or receive mail from - this is called a "mail cover" - without getting a warrant. Mail covers are a low-tech form of "traffic analysis," which we’ll discuss in the section dealing with electronic surveillance.

You don’t have any privacy in what you write on a postcard, either. By not putting your correspondence in an envelope, you’ve knowingly exposed it, and the government can read it without a warrant.

Police at the door: Police in your home or office when it’s open to the public?

The police may be able to come into your home or office if you have opened those places to the public - but you can also ask them to leave, just as if they were any other members of the public. If they don’t have a warrant, or don’t qualify for any of the warrant exceptions, they have no more right to stay once you’ve asked them to leave than any other trespasser. However, undercover agents or officers need not announce their true identities, so asking all cops to leave the room before a meeting is not going provide any protection.

Search Warrants Are Generally Required For Most Searches and Seizures.

The Fourth Amendment requires that any search or seizure be reasonable. The general rule is that warrantless searches or seizures are automatically unreasonable, though there are many exceptions.

To get a warrant, investigators must go to a neutral and detached magistrate and swear to facts demonstrating that they have probable cause to conduct the search or seizure. There is probable cause to search when a truthful affidavit establishes that evidence of a crime will probably be found in the particular place to be searched. Police suspicions or hunches aren't enough - probable cause must be based on actual facts that would lead a reasonable person to believe that the police will find evidence of a crime.

In addition to satisfying the Fourth Amendment's probable cause requirement, search warrants must satisfy the particularity requirement. This means that in order to get a search warrant, the police have to give the judge details about where they are going to search and what kind of evidence they are searching for. If the judge issues the search warrant, it will only authorize the police to search those particular places for those particular things.

Police at the door: Search warrants.

What should you do if a police officer comes to your home or office with a search warrant?

Be polite. Do not get in the officers' way, do not get into an argument with them or complain, even if you think your rights are being violated. Never insult a police officer. But you should say "I do not consent to this search." If they are properly authorized, they will search anyway. But if they are not, then you have reserved your right to challenge the search later.

Ask to see the warrant. You have a right to examine the warrant. The warrant must tell in detail the places to be searched and the people or things to be seized, and may limit what time of day the police can search. A valid warrant must have a recent date (usually not more than a couple of weeks), the correct address, and a judge's or magistrate's signature. If the warrant appears incomplete, indicates a different address, or otherwise seems mistaken, politely point this out to the police.

Clearly state that you do not consent to the search. The police don't need your consent if they have a warrant, but clearly saying "I do not consent to this search" will limit them to search only where the warrant authorizes. If possible, have witnesses around when you say it.
Do not resist, even if you think the search is illegal, or else you may be arrested. Keep your hands where the police can see them, and never touch a police officer. Do not try to leave if the police tell you to stay - a valid warrant gives them the right to detain any people that are on the premises while the search is conducted. You are allowed to observe and take notes of what the officers do, though they may tell you to sit in one place while they are conducting the search.

Don't answer any questions. The Fifth Amendment guarantees your right not to answer questions from the police, even if they have a warrant. Remember that anything you say might be used against you later. If they ask you anything other than your name and address, you should tell them "I choose to remain silent, and will not answer any questions without a lawyer." If you say this, they are legally required to stop asking you questions until you have a lawyer with you.

Take notes. Write down the police officers' names and badge numbers, as well as the names and contact information of any witnesses. Write down, as best you can remember, everything that the police say and everything you say to them. Ask if you can watch the search, and if they say yes, write down everything that you see them search and/or seize (you may also try to tape or take pictures, but realize that this may escalate the situation). If it appears they are going beyond what is authorized by the warrant, politely point this out.

Ask for an inventory. At the conclusion of the search, the police should typically provide an inventory of what has been seized; if not, request a copy but do not sign any statement that the inventory is accurate or complete.

Call a lawyer as soon as possible. If you don't have a lawyer, you can call EFF and we'll try to find you one.

Police at the door: Computer searches and seizures.

If the police believe a computer is itself evidence of a crime - for example, if it is stolen or was used to commit a crime - they will usually seize it and then search its contents later. However, if the evidence is just stored on the computer - for example, you have computer records that contain information about the person they are investigating - instead of seizing the whole machine, the police may choose to:

Search the computer and print out a hard copy of the particular files they are looking for (this is rarely done)
Search the computer and make an electronic copy of the particular files
Create a duplicate electronic copy of all of the computer's contents (this is called "imaging" or creating a "bitstream copy" of the computer hard drive) and then search for the particular files later

"Sneak and Peek" Search Warrants Are Easier to Obtain Than They Used to Be

Generally, police officers serving a warrant must "knock and announce" - that is, give you notice that they are the police and are serving a warrant (although they might not do this if they reasonably suspect that they will be put in danger, or that evidence will be destroyed, if they give such notice). If they have a warrant, they can enter and search even if you aren't home - but they still have to leave a copy of the warrant and an inventory of what they seized, so you'll know that your place was searched.

However, thanks to the USA PATRIOT Act, it is much easier for law enforcement to get permission from the court to delay notice rather than immediately inform the person whose premises are searched, if agents claim that giving notice would disrupt the investigation. Since the goal is not to tip the suspect off, these orders usually don't authorize the government to actually seize any property - but that won't stop them from poking around your computers.

The delay of notice in criminal cases can last months. The average delay is 30 to 90 days. In the case of super-secret foreign intelligence surveillance to be discussed later, the delay lasts forever - no one is ever notified, unless and until evidence from the search is introduced in open court.

The risk of being targeted with such a "sneak-and-peek" warrant is very low, although rising quickly. Law enforcement made 47 sneak-and-peek searches nationwide from September 2001 to April 2003 and an additional 108 through January 2005, averaging about fifty per year, mostly in drug cases. We don't know how many foreign intelligence searches there are per year - it's secret, of course - but we'd guess that it's much more common than secret searches by regular law enforcement.

Secret searches can be used to install eavesdropping and wiretapping devices. Secret searches may also be used to install a key-logging device on your computer. A key-logger records all of the keystrokes that you make on the computer's keyboard, for later retrieval by the police who installed it. So if you are concerned about government surveillance, you should check your office computers for new added hardware that you don't recognize - especially anything installed between the keyboard and the computer - and remove it. A hardware key-logger often looks like a little dongle in between the keyboard plug and computer itself. Keyghost is an example of a hardware key-logger.

However, the government also has the capability to remotely install software key-loggers on your computer - or search the contents of your hard drive, or install surveillance capability on your computer - using its own spyware. There were rumors of such capability a few years ago in news reports about a government software program code-named “Magic Lantern” that could be secretly installed and monitored over the Internet, without the police ever having to enter your house or office. More recently, news reports revealed that the government had in one case been able to hack into a computer remotely and install software code-named “CIPAV” (the "Computer and Internet Protocol Address Verifier"), which gave the government the IP addresses with which the infected computer communicated.

In response to a survey, all of the major anti-spyware companies claimed that their products would treat government spyware like any other spyware programs, so you should definitely use some anti-spyware product to monitor your computer for such programs. It's possible that a spyware company may receive a court order requiring it not to alert you to the presence of government spyware (several of the companies that were surveyed declined to say whether they had received such orders), but you should still use anti-spyware software if only to protect yourself against garden-variety spyware deployed by identity thieves and commercial data harvesters.

There Are Many Fourth Amendment Exceptions to the General Rule of Warrants

In some cases, a search can be reasonable - and thus allowed under the Fourth Amendment - even if the police don't have a warrant. There are several key exceptions to the warrant requirement that you should be aware of.

Consent. The police can conduct a warrantless search if you voluntarily consent to the search - that is, if you say it's OK. In fact, any person who the police reasonably think has a right to use or occupy the property, like a roommate or guest in your home, or a coworker at your office, can consent to the search. You can make clear to the people you share a home or office with that they do not have your permission to consent to a search and that if police ask, they should say no.

Privacy tip: Don't accidentally consent!

If the police show up at your door without a warrant, step outside then close and lock the door behind you - if you don't, they might just walk in, and later argue that you implied an invitation by leaving the door open. If they ask to come in, tell them "I do not consent to a search." Tell roommates, guests, coworkers and renters that they cannot consent on your behalf.

Administrative searches. In some cases, the government can conduct administrative searches. These are searches done for purposes other than law enforcement; for example, for a fire inspection. Court authorization is required for involuntary administrative searches, although the standards are lower. The only time the government doesn't need a warrant for an administrative search is when they are searching businesses in highly regulated industries such as liquor, guns, strip mining, waste management, nuclear power, etc. This exception to the warrant requirement clearly does not apply to the average homeowner, activist organization or community group.

Privacy tip: Just because they're "inspectors" doesn't mean you have to let them in!

If someone shows up at your home or office claiming to be a fire inspector, building code inspector, or some other non-law enforcement government employee who wants to inspect the premises, you can tell them to come back with a warrant. You don't have to let them in without a warrant!

Exigent circumstances. Exigent circumstances are emergency situations where it would be unreasonable for the police to wait to get a warrant, like if a person is calling for help from inside your house, if the police are chasing a criminal suspect who runs into an office or home, or if evidence will be destroyed if the police do not act immediately.

Privacy tip: Don't get tricked into consenting!

Police could try to get your consent by pressuring you, or making you think that you have to let them in. For example, they may show up at your door claiming that your neighbor saw someone breaking into your home or office, saw a criminal suspect entering the premises, or heard calls for help, and that they need to take a look around. You should never physically interfere if they demand to come in (which they will do if there are indeed exigent circumstances), but no matter what they say or do, keep saying the magic words: "I do not consent to a search."

Plain view. The police can make a warrantless search or seizure if they are lawfully in a position to see and access the evidence, so long as that evidence is obviously incriminating. For example, if the police enter a house with a valid search warrant to search for and seize some stolen electronics and then see a bag of drugs in plain view on the coffee table, they can seize the drugs too, even though the warrant didn't specifically authorize that seizure. Similarly, the police could seize the drugs without a warrant, or look at any other documents or things left in plain view in the house, if there were exigent circumstances that led the police into the house - for example, if a suspect they were chasing ran into the house, or if they heard gunshots from inside. Even a law-abiding citizen who does not have any contraband or evidence that the police would want to seize may still have sensitive documents in plain view that one would not want the authorities to see.

The plain view exception alone does not allow the police to enter your home or office without a warrant. So, for example, even if the police see evidence through your window, they cannot enter and seize it. However, plain view can combine with other exceptions to allow searches that might otherwise require a warrant. For example, if the person with the bag of drugs in the previous example saw the police looking through his window, then grabbed the bag and ran towards the bathroom as if he was about to flush the evidence down the toilet, that would be an exigent circumstance and the police could enter without a warrant to stop him.

Automobiles. Since cars and other vehicles are mobile, and therefore might not be around later if the police need to go get a warrant, the police can search them without one. They still need probable cause, though, because you do have a privacy interest in your vehicle.

If the police have probable cause, they can search the entire vehicle (including the trunk) and all containers in the vehicle that might contain the object for which they are searching. For example, if the police have probable cause to believe that drugs are in the vehicle, they can search almost any container, but if they have probable cause to believe that a murder suspect is hiding inside the vehicle, they must limit their search to areas where a person can hide.

Also, it's important to know that the "plain view" exception is often applied to cars. That means that the police aren't conducting a search just by looking through your car windows, or even by shining a flashlight in your car. And if they see evidence inside your car, that can then give them probable cause to search the rest of the vehicle under the automobile exception.

Police at the (car) door: What if I get pulled over?

If you are pulled over by a police officer, you may choose to stop somewhere you feel safe, both from traffic and from the officer herself. In other words, you can pull into a lighted gas station, or in front of someone's home or somewhere there are other people present, rather than stopping on a dark road, so long as you indicate to the officer by your driving that you are in fact stopping. You are required to show the officer your license, insurance and registration. Keep your hands where the officer can see them at all times. For example, you can wait to get your documentation out when the officer is standing near your car so that she can watch what you are doing and have no cause to fear that you are going into the glove box for a weapon. Be polite and courteous.

Airport searches. As you certainly know if you've flown recently, the government is allowed to search you and all your luggage for bombs and weapons before you are allowed to board a plane, without a warrant. Always assume that the government will look in your bags when you fly, and pack accordingly.

Border searches. The government has the right to warrantlessly search travelers at the border, including international airports, as part of its traditional power to control the flow of items into and out of the country. The case law distinguishes between "routine" searches, which require no cause, and "non-routine" searches, which require reasonable suspicion, but no warrant. "Non-routine" searches include strip searches, cavity searches, involuntary X-rays and other particularly invasive investigative techniques. Several courts have found that searching the contents of your laptop or other electronic devices is "routine" and doesn't require a warrant or even reasonable suspicion.

One solution to this problem is to bring a blank "traveling" laptop and leave your personal information at home. You could then access the information that you left at home over the internet by using a VPN or other secure method to connect to a server where you've stored the information.

However, bringing a clean laptop means more than simply dragging files into the trash. Deleting files will not remove them from your hard drive. See our software and technology article on secure deletion for details.

Another solution is to use password-based disk encryption to prevent border agents from being able to read your files. The consequences of refusing to disclose a password under those circumstances are difficult to predict with certainty, but non-citizens would face a significant risk of being refused entry to the country. Citizens cannot be refused entry, but could be detained until the border agents decide what to do, which may include seizing your computer.

Stop and frisk searches. The police can stop you on the street and perform a limited "pat-down" search or "frisk" - this means they can feel around your outer clothing for concealed weapons.

The police don't need probable cause to stop and frisk you, but they do at least need to have a reasonable suspicion of criminal activity based on specific facts. This is a very low standard, though, and the courts usually give the police a lot of leeway. For example, if a police officer is suspicious that you're carrying a concealed weapon based on the shape of a lump under your jacket or the funny way that you're walking, that's usually enough.

If, while patting you down, a police officer feels something that he reasonably believes is a weapon or an illegal item, the officer can reach into your clothes and seize that item. Search Incident to Lawful Arrest

Search Incident to Arrest (SITA) doctrine is an exception to the general requirement that police obtain a warrant before conducting a search. The purpose of this exception is to protect the officer by locating and seizing any weapons the person has and to prevent the destruction of any evidence on the person. According to the SITA doctrine, if an arrest is valid, officers may conduct a warrantless search of the arrestee and the area and objects in close proximity - i.e. the "grab area" - at about the same time as the arrest.

Officers may also perform inventory searches of the arrested person at the time of the arrest or upon arrival at the jail or other place of detention.

So, the police are allowed to search your clothing and your personal belongings after they've arrested you. They can also search any area nearby where you might conceal a weapon or hide evidence. If you are arrested inside a building, this usually means they can search the room they found you in but not the entire building. If you are arrested while driving, this means they can search inside the car, but not the trunk. But if they impound the car, then they can search the trunk as part of an inventory search. This is another example of the way that multiple exceptions to the warrant requirement can combine to allow the police a lot of leeway to search without going to a judge first.

When searches are delayed until some time after the arrest, courts generally have allowed warrantless searches of the person, including containers the arrestee carries, while rejecting searches of possessions that were within an arrestee's control. These no longer present any danger to the officer or risk of destruction because the arrestee is now in custody.

The question remains whether the SITA doctrine authorizes warrantless searches of the data on cell phones and computers carried by or located near the arrestee. There are very few cases addressing this question. In one case in Kansas, for example, the arresting officer downloaded the memory from the arrestee's cellphone for subsequent search. The court found that this seizure did not violate the Fourth Amendment because the officer only downloaded the dialed and incoming numbers, and because it was imperative to preserve the evidence given the volatile, easily destroyed, nature of cell phone memory.

In contrast, in another case in California, the court held that a cellphone search was not justified by the SITA doctrine because it was conducted for investigatory reasons rather than out of a concern for officer safety, or to prevent the concealment or destruction of evidence. The officers could seize the phone, and then go obtain a warrant to do any searching of it. The decision rejected the idea that the data searched was not private, in light of the nature and amount of information usually stored on cell phones and laptops.

Police at the door: Arrest warrants

If the police arrive at your home or office with an arrest warrant, go outside, lock the door, and give yourself up. Otherwise, they'll just force their way in and arrest you anyway, and then be able to search nearby. It is better to just go peacefully without giving them an excuse to search inside.

Police at the door: Searches of electronic devices incident to arrest

If you are arrested, the officers are going to seize all the property on your person before you are taken to jail. If you have a cell phone or a laptop, they will take that too. If you are sitting near a cell phone or laptop, they may take those as well. The SITA doctrine may allow police to search the data. It many also allow copying for later search, though this is well beyond what the SITA doctrine's original justification would allow.

You can and should password protect your devices to prevent this potentially unconstitutional privacy invasion. But for much stronger protection, consider protecting your data with file and disk encryption.

Prudent arresting officers will simply secure the devices while they get a warrant. There's nothing you can do to prevent that. Do not try to convince the officers to leave your phone or laptop behind by disavowing ownership. Lying to a police officer can be a crime. Also, prosecutors may use your statements against you later to argue that you do not have the right to challenge even an illegal search or seizure of the device, while still being able to introduce information stored on the device against you.

Subpoenas. Another Powerful Investigative Tool

In addition to search warrants, the government has another very powerful legal tool for getting evidence - the subpoena. Subpoenas are legal documents that demand that someone produce specific documents or appear in court to testify. The subpoena can be directed at you to produce evidence you have about yourself or someone else, or at a third party to produce evidence they have collected about you.

Subpoenas demand that you produce the requested evidence, or appear in court to testify, at some future time. Search warrants, on the other hand, are served and executed immediately by law enforcement with or without your cooperation.

Subpoenas, unlike search warrants, can be challenged in court before compliance. If you are the recipient of the subpoena, you can challenge it on the grounds that it is too broad or that it would be unduly burdensome to comply with it. If a judge agrees, then the court may quash the subpoena so you don't have to produce the requested evidence. You may also be able to quash the subpoena if it is seeking legally privileged material, or information that is protected by the First Amendment, such as a political organization's membership list or information to identify an anonymous speaker. If the subpoena is directed to a third party that holds information about you, and you find out about it before compliance, then you can make a motion to quash the subpoena on the grounds of privilege or constitutional rights regardless of whether the third party decides it would otherwise comply. However, you have to do so before the compliance date. Subpoenas that are used to get records about you from third parties sometimes require that you be notified, but usually do not.

Subpoenas are issued under a much lower standard than the probable cause standard used for search warrants. A subpoena can be used so long as there is any reasonable possibility that the materials or testimony sought will produce information relevant to the general subject of the investigation.

Subpoenas can be issued in civil or criminal cases and on behalf of government prosecutors or private litigants; often, subpoenas are merely signed by a government employee, a court clerk, or even a private attorney. In contrast, only the government can get a search warrant.

Police at the door: Subpoenas

What should you do if a government agent (or anyone else) shows up with a subpoena?

NOTHING.

Subpoenas are demands that you produce evidence at some time in the future. A subpoena does not give anyone the right to enter or search your home or office, nor does it require you to hand over anything immediately. Even a "subpoena forthwith", which asks for immediate compliance, can not be enforced without first going to a judge.

So, if someone shows up with a subpoena, don't answer any questions, don't invite them in, and don't consent to a search - just take the subpoena, say thank you, close the door and call a lawyer as soon as possible!

THIS SELECTION IS PART OF A LARGER ENTRY ON SURVEILLANCE SELF-DEFENSE AND CAN BE FOUND ON THE
ELECTRONIC FRONTIER FOUNDATION'S SSD WEBSITE AT https://ssd.eff.org/